ISSN:
1550-7408
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
. Programmed DNA rearrangements, including DNA degradation, characterize the development of the soma from the germline in a number of developmental systems. Pddl p (programmed DNA degradation 1 protein), a development-specific polypeptide in Tetrahymena, is enriched in developing macronuclei (anlagen) and has been implicated in DNA elimination and nucleolar biogenesis. Here, immunocytochemistry and fluorescent in situ hybridization (FISH) were employed to follow Pddl p and two nucleolar markers (Nopp52 and rDNA) during macronuclear development. Both Pdd 1p and Nopp52 localize to subnuclear structures, each of which resemble nucleoli. However, while true nucleoli form and persist during development, Pdd 1p-positive structures are only present for a brief period of macronuclear differentiation. Accordingly, two distinct organelles can be recognized in anlagen: (1) Pdd 1p-positive structures, which lack Nopp52 and rDNA, and (2) developing nucleoli which contain rDNA and Nopp52 but lack Pdd 1p. Taken together with recent data corroborating Pdd 1p's role in DNA elimination, we favor the hypothesis that Pdd 1p structures are unique, short-lived organelles, likely to function in programmed DNA degradation and not in nucleolar biogenesis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1550-7408.1997.tb05942.x
